Updated targetSdkVersion to leatest (19).

Fixes #198
Updated engine-android to use latest targetSdkVersion.
Rebased and fixed editor-android sdk version.
Updated android-maven-plugin to latest: 3.9.0 release candidate 1
Changelog: https://code.google.com/p/maven-android-plugin/wiki/Changelog
Merge pull request #274 from RotaruDan/targetSdkVersion

Updated targetSdkVersion to latest (19).